Monoculture farming is harming bees' microbiome

To measure the health of the microbiome of honeybees, researchers at the University of Lancaster in England analyzed the diversity of bacteria in bee bread, the longterm food supply stored in the hives of honeybees.

Scientists found less diverse bacterial communities inside hives close to acreage featuring a single species of grass, managed for livestock grazing. The bee bread in hives near coniferous forests managed for timber also hosted limited microbial diversity.

Healthier microbiomes were found in hives positioned near habitat with a greater diversity of plant species, including broadleaf woodland, rough grasslands and coastal landscapes.

Bees pick up different types of helpful bacteria from the different flowers they visit. If their foraging menu is less diverse, their bee bread and microbiomes will be too. Without a diverse microbiome, bees are more vulnerable to mold, parasites and infectious diseases.

"It is traditionally thought that monocultures, such as grazing land and timber forests, were bad for pollinators due to a lack of food continuance through the year," Lancaster researcher Philip Donkersley said in a news release. "However, our study suggests land use change may also be having an indirect detrimental effect on the microbiota of bee bread."

Researchers published their analysis of bee bread bacteria this week in the journal Ecology and Evolution.

"Since nutrition derived from bee bread and the microbiome therein directly affects the health of bees we therefore believe this demonstrates an indirect link between landscape composition and bee fitness," said Donkersley.

Researchers found microbiota diversity was also diminished in hives closer to urban centers, suggesting gardens in cities and suburbs aren't providing sufficient levels of good bacteria.

"Decreased bacterial diversity in bee breads near urban environments suggests that the increased range of non-native plants in gardens could be impacting bees' ability to get diverse microbiota," Donkersley said. "This may be evidence that bees suffer from foraging on non-native plants that they have not co-evolved with."